CODEWITHSUNDEEP
textawksedscriptingnewline
J. LS
J. LS

Reputation: 123

Adding new line to file with sed

I want to add a new line to the top of a data file with sed, and write something to that line.

I tried this as suggested in How to add a blank line before the first line in a text file with awk :

sed '1i\ \' ./filename.txt

but it printed a backslash at the beginning of the first line of the file instead of creating a new line. The terminal also throws an error if I try to put it all on the same line ("1i\": extra characters after \ at the end of i command).

Input :

1 2 3 4 
1 2 3 4 
1 2 3 4

Expected output

14
1 2 3 4 
1 2 3 4 
1 2 3 4

Upvotes: 1

Views: 2298

Answers (2)

hek2mgl
hek2mgl

Reputation: 157947

Basially you are concatenating two files. A file containing one line and the original file. By it's name this is a task for cat:

cat - file <<< 'new line'
# or 
echo 'new line' | cat - file

while - stands for stdin.

You can also use cat together with command substitution if your shell supports this:

cat <(echo 'new line') file

Btw, with sed it should be simply:

sed '1i\new line' file

Upvotes: 2

Ed Morton
Ed Morton

Reputation: 203149

$ sed '1i\14' file
14
1 2 3 4
1 2 3 4
1 2 3 4

but just use awk for clarity, simplicity, extensibility, robustness, portability, and every other desirable attribute of software:

$ awk 'NR==1{print "14"} {print}' file
14
1 2 3 4
1 2 3 4
1 2 3 4

Upvotes: 2

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